linux-kernel - Re: [PATCH v3 2/4] media: dw100: Implement dynamic vertex map update

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Message-ID: <20260210180703.GC2502896@killaraus.ideasonboard.com>
Date: Tue, 10 Feb 2026 20:07:03 +0200
From: Laurent Pinchart <laurent.pinchart@...asonboard.com>
To: Stefan Klug <stefan.klug@...asonboard.com>
Cc: Xavier Roumegue <xavier.roumegue@....nxp.com>,
	Mauro Carvalho Chehab <mchehab@...nel.org>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	Clark Williams <clrkwllms@...nel.org>,
	Steven Rostedt <rostedt@...dmis.org>, linux-media@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-rt-devel@...ts.linux.dev,
	Nicolas Dufresne <nicolas@...fresne.ca>
Subject: Re: [PATCH v3 2/4] media: dw100: Implement dynamic vertex map update

Hi Stefan,

Thank you for the patch.

On Thu, Jan 29, 2026 at 12:43:11PM +0100, Stefan Klug wrote:
> Implement dynamic vertex map updates by handling the
> V4L2_CID_DW100_DEWARPING_16x16_VERTEX_MAP control during streaming. This
> allows to implement features like dynamic zoom, pan, rotate and dewarp.
> 
> To stay compatible with the old version, updates of
> V4L2_CID_DW100_DEWARPING_16x16_VERTEX_MAP are ignored during streaming
> when requests are not used. Print a corresponding warning once.
> 
> Signed-off-by: Stefan Klug <stefan.klug@...asonboard.com>
> 
> ---
> 
> Changes in v2:
> - Replaced the manual warn once by dev_warn_once(). This changes the
>   frequency from once per context to once per boot which was agreed to
>   be enough.
> - Renamed user_map_needs_update to user_map_is_dirty as it is more
>   expressive and fits to user_map_is_set
> - Fixed indentation issue found by Media CI
> ---
>  drivers/media/platform/nxp/dw100/dw100.c | 24 ++++++++++++++++++------
>  1 file changed, 18 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/media/platform/nxp/dw100/dw100.c b/drivers/media/platform/nxp/dw100/dw100.c
> index 1cb895da9912371a2b23ca62412c572d9cb75c00..d2b1c62b52db47ea1d2242caaf334fff30c6f366 100644
> --- a/drivers/media/platform/nxp/dw100/dw100.c
> +++ b/drivers/media/platform/nxp/dw100/dw100.c
> @@ -98,6 +98,7 @@ struct dw100_ctx {
>  	unsigned int			map_width;
>  	unsigned int			map_height;
>  	bool				user_map_is_set;
> +	bool				user_map_is_dirty;
>  
>  	/* Source and destination queue data */
>  	struct dw100_q_data		q_data[2];
> @@ -293,11 +294,15 @@ static u32 dw100_map_format_coordinates(u16 xq, u16 yq)
>  	return (u32)((yq << 16) | xq);
>  }
>  
> -static u32 *dw100_get_user_map(struct dw100_ctx *ctx)
> +static void dw100_update_mapping(struct dw100_ctx *ctx)
>  {
>  	struct v4l2_ctrl *ctrl = ctx->ctrls[DW100_CTRL_DEWARPING_MAP];
>  
> -	return ctrl->p_cur.p_u32;
> +	if (!ctx->user_map_is_dirty)
> +		return;
> +
> +	memcpy(ctx->map, ctrl->p_cur.p_u32, ctx->map_size);
> +	ctx->user_map_is_dirty = false;
>  }
>  
>  /*
> @@ -306,8 +311,6 @@ static u32 *dw100_get_user_map(struct dw100_ctx *ctx)
>   */
>  static int dw100_create_mapping(struct dw100_ctx *ctx)
>  {
> -	u32 *user_map;
> -
>  	if (ctx->map)
>  		dma_free_coherent(&ctx->dw_dev->pdev->dev, ctx->map_size,
>  				  ctx->map, ctx->map_dma);
> @@ -318,8 +321,8 @@ static int dw100_create_mapping(struct dw100_ctx *ctx)
>  	if (!ctx->map)
>  		return -ENOMEM;
>  
> -	user_map = dw100_get_user_map(ctx);
> -	memcpy(ctx->map, user_map, ctx->map_size);
> +	ctx->user_map_is_dirty = true;
> +	dw100_update_mapping(ctx);
>  
>  	dev_dbg(&ctx->dw_dev->pdev->dev,
>  		"%ux%u %s mapping created (d:%pad-c:%p) for stream %ux%u->%ux%u\n",
> @@ -351,6 +354,7 @@ static int dw100_s_ctrl(struct v4l2_ctrl *ctrl)
>  	switch (ctrl->id) {
>  	case V4L2_CID_DW100_DEWARPING_16x16_VERTEX_MAP:
>  		ctx->user_map_is_set = true;
> +		ctx->user_map_is_dirty = true;
>  		break;
>  	}
>  
> @@ -405,6 +409,7 @@ static void dw100_ctrl_dewarping_map_init(const struct v4l2_ctrl *ctrl,
>  	}
>  
>  	ctx->user_map_is_set = false;
> +	ctx->user_map_is_dirty = true;
>  }
>  
>  static const struct v4l2_ctrl_type_ops dw100_ctrl_type_ops = {
> @@ -1478,6 +1483,13 @@ static void dw100_device_run(void *priv)
>  	v4l2_ctrl_request_setup(src_buf->vb2_buf.req_obj.req,
>  				&ctx->hdl);
>  
> +	if (src_buf->vb2_buf.req_obj.req)
> +		dw100_update_mapping(ctx);
> +	else if (ctx->user_map_is_dirty)
> +		dev_warn_once(&ctx->dw_dev->pdev->dev,
> +			      "V4L2 requests are required to update the vertex map dynamically"

Missing \n

> +		);

The closing parenthesis goes at the end of the previous line.

With those small issues fixed,

Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>

> +
>  	v4l2_ctrl_request_complete(src_buf->vb2_buf.req_obj.req,
>  				   &ctx->hdl);
>  

-- 
Regards,

Laurent Pinchart